Eye fundus inspection apparatus

ABSTRACT

Eye fundus inspection apparatus ( 500 ) comprising: —illumination means ( 12 ) comprising at least a light source ( 121, 123, 124, 126 ) and adapted to project a first light beam ( 1 ) towards a retina ( 101 ) of an eye ( 100 ); —an optical lighting path ( 1 A) for said first light beam; —acquisition means ( 27 ) adapted to receive a second light beam ( 2 ) coming from the retina; —an optical acquisition path ( 2 A) for said second light beam; —scanning means ( 17 ) adapted to scan said first light beam ( 1 ) on the retina with a linear movement, according to a first scanning direction (S 1 ), or with a circular movement about a rotation axis (A), according to a second scanning direction (S 2 ); —light beam separating means ( 16 ) adapted to define separate passage zones for said first and second light beams ( 1, 2 ) at a pupil of the eye; —a control unit ( 120 ) adapted to control operation of said inspection apparatus; —first light beam shaping means ( 11 ) and second light beam shaping means ( 23, 271, 272 ) that allow obtaining improved retinal images.

The present invention relates to an eye fundus inspection apparatus.

The apparatus according to the invention is particularly suitable foruse in ophthalmology, when it is necessary to acquire images of theretina of the eye.

The use of eye fundus inspection apparatus adapted to acquire images ofthe retina is widely known.

Among these, eye fundus inspection apparatus of confocal type are alsoknown.

For reasons of constructional simplicity, eye fundus inspectionapparatus of confocal type of the type with line scanning, in particularthose that use LED light sources, are of particular industrial andcommercial interest.

Examples of these eye fundus inspection apparatus of confocal type withline scanning are described in the patent documents U.S. Pat. Nos.7,331,669, 7,831,106B2, US20140232987A1, WO2016/037980A1 andUS20160227998A1.

Inspection apparatus of this type are arranged to scan the retina with alight beam that illuminates a linear shaped retinal region.

In these apparatus, the light reflected by the retina is collected andpassed through a confocal diaphragm provided with a suitably shapedconfocal opening (for example slit shaped) to reduce the amount ofparasitic light coming from unwanted reflections.

The reflected light beam, passing through the confocal diaphragm, isreceived by an acquisition sensor adapted to acquire images of theretina.

In some construction designs, these apparatus can use one or more LEDsas light sources. In these cases, considering the limited level ofradiance of the LEDs, it is not possible to project a light outputsufficient to acquire images of the retina, if the illuminated retinalregion is very narrow.

Consequently, the light beam that illuminates the retina is typicallyshaped so that the retinal region illuminated has a linear shape ofrelatively high width, for example comprised between 1/100 and ⅕ of itslength.

This means that the confocal diaphragm also has a confocal opening ofrelatively high width, with approximately the same ratio between widthand length.

The relatively high width of the opening of the confocal diaphragmreduces its capacity to efficiently filter the unwanted parasitic lightcoming from zones other than the retina, in particular the scatteredlight from the crystalline lens, particularly intense in the case inwhich the eye examined is affected by cataract.

The parasitic light coming from the crystalline lens gives rise tomarked “blurring” effects that can make the images acquired useless formedical diagnosis.

A particular type of confocal eye fundus inspection apparatus with linescanning comprises apparatus destined to provide fluorescence images ofthe retina.

These inspection apparatus illuminate the retina with an excitationlight having wavelength typically in the blue or green region. Theycomprise, besides the components described above, filter means capableof blocking the reflected excitation light and allowing fluorescencelight, emitted by particular fluorescent substances present on theretina and having higher wavelengths with respect to the wavelengths ofthe illumination light, to pass towards the sensor.

As is known, in the case of acquisition of fluorescence images of theretina, the crystalline lens of the eye absorbs a part of the excitationlight and emits fluorescence light that overlaps the fluorescence lightemitted by the retina, thereby reducing the contrast of the imagesacquired by the acquisition sensor (presence of “blurring” effects).

To reduce the influence of parasitic light coming from the crystallinelens on the images of the retina, some prior art apparatus, for examplethose described in the patent documents cited above, are provided withlight beam separating means (for example a separation diaphragm)destined to create, at the level of the crystalline lens, an opticalseparation between the illumination light beam and the light beamreflected by the retina. Separation of the beams at the level of thecrystalline lens reduces the blurring effects in the images acquired bythe sensor, but without reducing them sufficiently.

The solutions proposed in the patent documents cited do not providepractical solutions that satisfactorily reduce the parasitic lightscattered by the crystalline lens or emitted, by fluorescence,therefrom.

The patent document WO20170049323A1 describes a solution for improvingthe level of contrast in the images of the retina (whether coloured orfluorescence) acquired.

In the apparatus described in this patent document, an illuminationlight beam is scanned along the retina with a movement in subsequentsteps, according to a scanning direction.

At a series of discrete positions, separate from one another, the lightbeam illuminates different retinal regions having linear shape withrelatively high width.

A light beam reflected by the retina is passed through a confocaldiaphragm and directed towards an acquisition sensor that acquires aplurality of partial images of the retina, each of which shows a retinalregion illuminated with the light beam positioned in a correspondingdiscrete position.

The retinal region shown in each of these images has a lengthapproximately equal to the length of the region illuminated by the lightbeam and a width wider than the width of the region illuminated by thelight beam.

Each partial retinal image shows a plurality of parallel regions of theretina having a same length, side by side along their longer side andarranged in succession according to the scanning direction of the lightbeam.

These parallel regions comprise, in succession according to the scanningdirection, a first “dark” zone, a first slightly brighter transitionzone, a brighter central zone and a second “dark” zone.

Each region has a linear shape oriented according to a directionperpendicular to the scanning direction.

The partial images of the retina, thus acquired, are combined toreconstruct an overall retinal image.

The patent document mentioned above also describes a processingprocedure of the images which provides for:

-   -   processing the partial images of the retina, described above, to        acquire data indicative of the light level of the “dark” zones        present in the aforesaid images;    -   correcting the overall retinal image based on the data thus        acquired to reduce the “blurring” effects caused by the presence        of parasitic light.

The solution illustrated above has some drawbacks.

Firstly, it is not very efficient for obtaining a satisfactory reductionof the parasitic light scattered or emitted, through fluorescence, bythe crystalline lens.

Another drawback consists in the need to acquire a large number ofpartial images of the retina to reconstruct an overall image. Thisrequires the provision of relatively complex and costly data processingmeans in order to obtain an overall retinal image without inconvenientdelays for the user. Moreover, there is a high probability of theoverall retinal image thus reconstructed having reconstructionartifacts.

A further drawback consists in the fact of requiring complicated andcostly scanning means of the light beam, which can move the light beamwith rapid controlled movements so that each of the partial images ofthe retina is acquired with the light beam stopped in one of thediscrete positions mentioned above to prevent or reduce the presence ofmotion artifacts in the images acquired.

A further drawback consists in the fact that the acquisition time toacquire an overall retinal image is relatively long. Therefore, there isa high probability of the overall retinal image acquired being affectedby motion artifacts of the eye.

The main aim of the present invention is to provide an eye fundusinspection apparatus, of confocal line scanning type, which solves theaforesaid problems of prior art.

Within this aim, an object of the present invention is to provide an eyefundus inspection apparatus capable of producing colour or fluorescenceimages of the retina, which have a high level of contrast, also in casesin which the eye being examined is affected by cataract or otherdisorders.

A further object of the present invention is to provide an eye fundusinspection apparatus capable of producing wide field images of theretina, which have a high degree of contrast, also in cases in which theeye being examined is affected by cataract or other disorders.

A further object of the present invention is to provide an eye fundusinspection apparatus capable of performing quantitative measurements offluorescence of the retina.

A further object of the present invention is to provide an eye fundusinspection apparatus that is easy to produce on an industrial scale, atcompetitive costs.

This aim and these objects, together with other objects that will bemore apparent from the subsequent description and from the accompanyingdrawings, are achieved according to the invention by an eye fundusinspection apparatus according to claim 1 and to the related dependentclaims, proposed hereunder.

Characteristics and advantages of the eye fundus inspection apparatusaccording to the invention will be more apparent with reference to thedescription given below and to the accompanying figures, provided purelyfor explanatory and non-limiting purposes, wherein:

FIGS. 1, 2, 3, 4 and 5 schematically illustrate some embodiments of theeye fundus inspection apparatus according to the invention;

FIGS. 6, 7, 8, 9 and 10 schematically illustrate some embodiments ofsubsystems forming the eye fundus inspection apparatus according to theinvention;

FIGS. 11, 12, 13, 14 and 15 schematically illustrate operation of theeye fundus inspection apparatus according to the invention;

FIG. 16 schematically illustrates the scattering and generation ofparasitic light inside the crystalline lens of the eye, when anillumination light beam passes through it.

The present invention relates to an eye fundus inspection apparatus 500,in particular of the confocal type with line scanning.

In a general definition thereof, the apparatus 500 comprises:

-   -   illumination means 12 comprising at least a light source and        adapted to project a first light beam 1 to illuminate a retina        101 of an eye 100;    -   an optical lighting path 1A for the first light beam 1;    -   acquisition means 27 adapted to receive a second light beam 2        coming at least partially from the retina;    -   an optical acquisition path 2A for the second light beam 2;    -   scanning means 17 adapted to move the first light beam 1 on the        retina.

The scanning means 17 can perform a linear scan, i.e., move the lightbeam 1 with a linear movement, according to a first rectilinear scanningdirection S1. In this way, the light beam 1, moving with respect to theretina according to the scanning direction S1, travels over andilluminates a retinal area having a substantially rectangular shape(FIG. 12).

Alternatively, the scanning means 17 can perform a circular scan, i.e.,move the light beam 1 with respect to the retina with a rotationalmovement about a rotation axis A, according to a circular scanningdirection S2. In this way, the light beam 1, moving with respect to theretina according to the scanning direction S2, travels across andilluminates an area of retina having a substantially circular shape(FIG. 13).

The apparatus 500 further comprises:

-   -   light beam separating means 16 adapted to define, at the level        of the pupil 102 of the eye, separate passage zones for the        first light beam 1 and for the second light beam 2;    -   a control unit 120 adapted to control operation of the        inspection apparatus. This control unit advantageously comprises        data processing means adapted to provide images of the retina;    -   first shaping means 11 of the light beams adapted to provide a        first passage section 1141 for the first light beam 1. The first        passage section 1141 is arranged in a position optically        conjugated with the retina and defines, on the retina, a light        projection region 1141A at which the first light beam 1 is        projected on the retina 101. The light projection region 1141A        has a linear shape with a length Lil, measured along a direction        perpendicular to the first scanning direction S1, or in radial        direction with respect to the second scanning direction S2, and        a width Wil, measured along a direction parallel to the first        scanning direction S1 or tangential with respect to the second        scanning direction S2;    -   second light beam shaping means 23, 271, 272 adapted to provide        a second passage section 2310 for the second light beam 2. The        second passage section 2310 is arranged in a position optically        conjugated with the retina and defines, on the retina, a light        acquisition region 231A from which the second light beam 2 comes        at least partially. The light acquisition region 231A has a        linear shape with a length Lim, measured along a direction        perpendicular to said first scanning direction S1 or radial with        respect to the second scanning direction S2, and a width Wim,        measured along a direction parallel to the first scanning        direction S1 or tangential with respect to the second scanning        direction S2.

For greater clarity of exposition, it is specified that, within thescope of the present invention, the definition “optically conjugated”identifies positioning in the exact position of optical conjugation orin a relatively small neighbourhood (with respect to the lengths of theoptical paths of the apparatus 500) of the exact position of opticalconjugation.

With reference to FIG. 1, there is now described a first embodiment ofthe invention.

In this embodiment, the apparatus comprises illumination means 12provided with at least a light source and adapted to project a firstlight beam 1 on the retina.

The apparatus 500 comprises a first optical lighting path 1A for thefirst light beam 1.

Preferably, the illumination means 12 comprise a light source 121,preferably of LED type.

In use of the apparatus 500, the light beam 1 passes along the opticalpath 1A towards the retina 101.

In the variant of embodiment shown in FIG. 6-(A), illumination means 12comprise, in addition to the light source 121, at least another lightsource 123, optically coupled to the lighting path 1A by means of atleast a dichroic mirror 125.

In this case, the illumination means 12 can advantageously be arrangedto provide a light suitable for the acquisition of various types ofphotos of the retina, for example infrared light or white light. Thelight generated by the sources 121, 123 is preferably collimated bymeans of the collimation lenses 122, 124.

In the embodiment shown in FIG. 6-(B), illumination means 12 comprise atleast a light source 126 capable of emitting an excitation lightsuitable to excite the fluorescent substances of the retina.

If necessary, the light generated by the light source 126 can becollimated through the collimation lens 127 and filtered by secondfilter means 129 to select a given bandwidth of wavelengths from thelight emitted by the source 126.

Preferably, illumination means 12 also comprise the aforementioned lightsources 121, 123. In this case, the various light sources are coupled tothe optical path 1A directly or by means of dichroic mirrors 128, 125.

The constructional solution shown in FIG. 6-(B) allows the apparatus 500to produce images using light reflected by the retina 101, as well asfluorescence images of the retina, as will be illustrated in more detailbelow.

The apparatus 500 further comprises first shaping means 11 adapted todefine a section of linear shape for the light beam 1.

With reference to FIGS. 7, 8 and 9, these show some variants ofembodiment of the first shaping means 11 of the light beam 1.

In the variant of embodiment shown in FIG. 7, the first shaping means 11comprise a projection diaphragm 114 arranged to be optically conjugatedwith the retina 101.

The projection diaphragm 114 advantageously comprises at least a firstprojection opening 1140 that defines a first passage section 1141 forthe light beam 1 projected by the light source 121.

The first passage section 1141 for the light beam 1 is opticallyconjugated with the retina and defines on the retina a linear shapedlight projection region 1141A (FIG. 11).

The light projection region 1141A has a length Lil measured along adirection perpendicular to the first scanning direction S1 and a lengthWil measured along a direction parallel to the first scanning directionS1 (linear scanning).

Moreover, the light projection region 1141A preferably has a length Lilmuch larger than its width Wil. For example, the ratio between the sizesWil/Lil can vary from ⅕ to 1/100.

According to the variants of embodiment shown in the FIGS. 8 and 9, theprojection diaphragm 114 of the first shaping means 11 is adjusted toprovide differentiated projection openings 1140, 1142 for the light beam1.

The projection openings 1140, 1142 have an elongated shape and arearranged to define passage sections 1141, 1143 of different length forthe light beam 1.

These passage sections, optically conjugated with the retina, definelight projection regions 1141A, 1143A of different length on the retina101 (FIGS. 11 and 15).

In general, the light projection regions 1141A, 1143A both have a linearshape.

The light projection region 1141A has a length Lil and width Wilmeasured as described for the variant of embodiment of FIG. 7.

The light projection region 1143A has a length Lil₂ measured along adirection perpendicular to the first scanning direction S1 and a lengthWil₂ measured along a direction parallel to the first scanning directionS1 (linear scanning).

Moreover, the light projection region 1143A preferably has a length Lil₂much longer than its width Wil₂. For example, the ratio between thesizes Wil/Lil can vary from ⅕ to 1/100.

According to the variants of embodiment of FIGS. 8 and 9, the passagesection 1141 has a length shorter than the passage section 1143 anddefines, on the retina 101, a light projection region 1141A having alength Lil shorter than the length Lil₂ of the light projection region1143A defined by the passage section 1143.

In the variant of embodiment of FIG. 8, the projection diaphragm 114comprises a first projection opening 1140 adapted to define a firstpassage section 1141 for the light beam 1, having a shorter length, anda second projection opening 1142 adapted to define a third passagesection 1143 for the light beam 1, having a longer length.

Advantageously, the projection diaphragm 114 is reversibly movable in afirst coupling position with the optical lighting path 1A, at which thefirst projection opening 1140 is optically coupled with the opticallighting path 1A, and in a second coupling position with the opticallighting path 1A, at which the second projection opening 1142 isoptically coupled with the optical lighting path 2A.

Preferably, the projection diaphragm 114 is moved by actuator means 29.

From the above, it is evident that, by moving the projection diaphragm114 between the two coupling positions described, it is possible toselectively vary the length of the retinal region illuminated by thelight beam 1, given that different passage sections 1141, 1143 definelight projection regions 1141A, 1143A of different length on the retina101.

In the variant of embodiment of FIG. 9, the projection diaphragm 114comprises a second projection opening 1142 arranged to define a thirdpassage section 1143 for the light beam 1, having a longer length.

The projection diaphragm 114 is operatively coupled with a mask 118reversibly movable in a first masking position and in a second maskingposition.

Preferably, the mask 118 is moved by actuation means 290.

At the first masking position, the mask 118 does not cover the secondprojection opening 1142.

At the second masking position, the mask 118 partially covers the secondprojection opening 1142 to obtain a projection opening corresponding tothe first projection opening 1140.

From the above, it is evident that, by moving the mask 118 between thetwo masking positions described, it is possible to selectively vary thelength of the retinal region illuminated by the light beam 1, given thateach position of the mask 118 corresponds to a different passage sectionfor the light beam 1.

The different passage sections 1140, 1143, thus obtained, define, on theretina 101, light projection regions 1141A, 1143A having differentiatedlength Lil, Lil₂, respectively a shorter length Lil and a larger lengthLil₂.

Other constructional solutions are possible for the first shaping means11 of the beam, evident for those skilled in the art.

For example, in a further constructional solution, not illustrated, thefirst shaping means of the beam can comprise a long and narrow mirrorarranged in a position conjugated with the retina 101 and which definesby reflection the linear section of the light beam 1. In this case, thepassage section 1141 for the light beam 1 is formed by the surface ofthis mirror.

The apparatus 500 comprises acquisition means 27 adapted to receive asecond light beam 2 coming from the retina 101 to allow the acquisitionof one or more images of the retina by the control unit 120.

The apparatus 500 comprises an optical acquisition path (or imagingoptical path) 2A for the second light beam 2.

In use of the apparatus 500, the light beam 2, starting from the retina101, passes along the optical acquisition path 2A until reaching theacquisition means 27.

The acquisition means 27 comprise at least a sensor capable of receivingthe light beam 2 at a receiving surface optically conjugated with theretina 101.

In the embodiment of FIG. 1, the acquisition means 27 can comprise atwo-dimensional sensor of CCD or C-MOS type.

The apparatus 500 comprises first scanning means 17 adapted to perform alinear scan, i.e., to move the light beam 1 projected on the surface ofthe retina 101 according to the first a scanning direction S1.

Advantageously, the first scanning means 17 also have the function ofde-scanning the light beam 2 and directing it along the opticalacquisition path 2A towards the acquisition means 27.

For the scanning means 17, various constructional solutions arepossible, for example using oscillating mirrors moved by galvanometersor resonance mechanisms, polygonal mirrors, micromirror arrays or thelike.

According to the embodiment of FIG. 1, the apparatus 500 comprisessecond shaping means of the beam 2 arranged along the opticalacquisition path 2A, in a position optically conjugated with the retina.

In the embodiment of FIG. 1, the second shaping means comprise aconfocal diaphragm 23.

The confocal diaphragm 23 preferably comprises at least a confocalopening 231 (of elongated shape) that defines a second passage section2310 for the light beam 2 directed towards the acquisition means 27.This passage section is optically conjugated with the retina and definesa corresponding light acquisition region 231A on the retina 101 (FIG.11).

The light acquisition region 231A has a linear shape with a length Limmeasured along a direction perpendicular to the first scanning directionS1 and a width Wim, measured along a direction parallel to the firstscanning direction S1.

According to the embodiment of FIG. 1, the apparatus 500 comprisessecond scanning means 171 adapted to scan the light beam 2 on thereceiving surface of the acquisition means 27.

Preferably, the second scanning means 171 have a movement synchronouswith the first scanning means 17.

Preferably, the first scanning means 17 and the second scanning means171 can be produced as a single assembly, for example using a resonantoscillating mirror with two mutually opposite reflecting surfaces.

According to the embodiment of FIG. 1, the apparatus 500 comprises lightbeam separating means 16 adapted to separate the light beam 1 from thelight beam 2 at the pupil 102 of the eye 100.

The light beam separating means can, for example, comprise at least aseparation diaphragm of the light beams.

Due to the light beam separation means 16, the light beam 2 passesthrough a predetermined zone of the pupil 102 separated from the zone ofpupil through which the light beam 1 enters the eye.

Preferably, the apparatus 500 comprises a first lens 15 arranged alongthe optical lighting path 1A between the beam shaping means 11 and thelight beam separation means 16.

Preferably, the apparatus 500 comprises an eyepiece 19, arranged alongthe optical lighting path 1A, between the first scanning means 17 andthe eye 100.

If necessary, the apparatus 500 can also comprise a scanning lens 18arranged between the first scanning means 17 and the eyepiece 19.

Preferably, the apparatus 500 also comprises a second lens 21, a thirdlens 25, an objective 26 arranged along the optical path 2A, between thebeam separation means 16 and the acquisition means 27.

The apparatus 1 advantageously comprises a control unit 120 adapted tocontrol its operation.

Advantageously, the control unit 120 comprises data processing means(for example a microprocessor) capable of executing softwareinstructions to perform the functions required.

Advantageously, the control unit 120 is adapted to execute one or moredata processing procedures to process the information acquired by theacquisition means 27.

Based on the information acquired by the acquisition means 27, thecontrol unit 120 is capable of acquiring and/or processing images of theretina and generating control signals to control operation of somecomponents of the apparatus 500, for example the illumination means 12,the acquisition means 27 and any actuator means comprised in theapparatus 500.

Preferably, the control unit 120 also comprises user interface means(not illustrated), for example a monitor, a keyboard and/or a mouse.

If necessary, the apparatus 500 can comprise first filter means 28adapted to allow passage towards the acquisition means 27 of only a partof the light beam 2 having a predefined band of wavelengths.

In a possible solution shown in FIG. 10-(A), the filter means 28comprise a filter 31 inserted in the imaging path 2A.

In the solution shown in FIG. 10-(B), the filter means 28 are arrangedto be able to be inserted in or removed from the acquisition path 2A. Tothis end, a filter 31 can be moved by an actuator 30, controlled by thecontrol unit 120 by means of suitable control signals.

With the solution shown in FIG. 10-(B) it is possible to produce amultifunctional apparatus 500, capable of acquiring images obtained withlight reflected by the retina as well as fluorescence images of theretina, as will be explained below.

With reference to FIG. 1, the general operation of the apparatus 500 isnow described in greater detail.

In use of the apparatus 500, the illumination means 12 provide the firstlight beam 1.

This latter is shaped by the shaping means 11 by passage through thepassage section 1141.

Moreover, the light beam 1 passes through the lens 15 and the light beamseparating means 16.

The light beam 1 is scanned by the scanning means 17 that direct ittowards the retina 101.

The light beam 1 passes through the scanning lens 18 and the eyepiece 19and enters the eye 100 to illuminate the retina 101.

On the retina 101, the light beam 1 illuminates a light projectionregion 1141A that moves along the retina, according to a first scanningdirection S1 (linear scanning) imposed by the scanning means 17,traveling across a first retinal area 1141B.

The light projection region 1141A has a linear shape with a length Lilmeasured along a direction perpendicular to the first scanning directionS1 and a width Wil measured along a direction parallel to the firstscanning direction S1 (FIG. 11).

Preferably, the light projection region 1141A has a length Lil muchlonger than its width Wil. For example, the ratio between the sizesWil/Lil can vary from ⅕ to 1/100.

Illumination of the retina 101 by the light beam 1 causes the formationof a light beam 2 exiting from the retina 101.

In particular, the light beam 2 can be formed by light reflected oremitted, by fluorescence (natural or induced), from the retina at alight acquisition region 231A that moves along the retina synchronouslywith the light projection region 1141A, according to the scanningdirection S1 imposed by the scanning means 17, traveling across a secondretinal area 231B (FIG. 11).

The light acquisition region 231A has a linear shape with a length Limmeasured along a direction perpendicular to the first scanning directionS1 and a width Wim measured along a direction parallel to the firstscanning direction S1.

Preferably, the light acquisition region 231A has a length Lim muchlonger than its width Wim. For example, the ratio between the sizesWim/Lim can vary from ⅕ to 1/100.

The light beam 2 from the retina 101 exits from the eye through thepupil 102, at a separate zone from the zone through which the light beam1 passes, and passes back through the eyepiece 19 and the scanning lens18.

The scanning means 17 descan the light beam 2 transforming it into afixed beam and simultaneously directing it along the optical path 2A,towards the light beam separating means 16.

The light beam 2 then passes through the lens 21, if necessary isfiltered by the filter means 28, passes through the confocal opening 231of the confocal diaphragm 23, which is fixed, passes through the lens25.

The second scanning means 171 scan the light beam 2 again,simultaneously directing it along the optical path 2A towards theacquisition means 27.

The light beam 2 passes through the lens 26 and reaches the receivingsurface of the acquisition means 27 that transmit information to thecontrol unit 120 to acquire one or more images of the retina 101.

A further embodiment of the apparatus 500 is shown in FIG. 2.

This embodiment has a structure and operation similar, in many aspects,to the embodiment of FIG. 1.

Unlike this latter, the first scanning means 17 do not performdescanning of the beam 2 but are simply arranged to direct the lightbeam 2 towards the beam separating means and subsequently along theoptical acquisition path 2A.

The second scanning means 171 are absent in this embodiment of theinvention.

In the embodiment of FIG. 2 of the apparatus 500, the first shapingmeans 11 of the light beam 1 are identical to the first shaping meansalready described in relation to FIGS. 1, 7, 8 and 9. They comprise aprojection diaphragm 114 or other shaping means adapted to define apassage section 1141 identical to that of the embodiment of FIG. 1described above.

In the embodiment of FIG. 2 of the apparatus 500, the second shapingmeans of the light beam 2 comprise a confocal diaphragm 23 identical tothe one described for the embodiment of FIG. 1 described above.

However, in this case the confocal diaphragm 23 is produced so that itcan move synchronously with the movement of the scanning means 17.

A further embodiment of the apparatus 500 is shown in FIG. 3.

This embodiment has a structure and operation similar, in many aspects,to the embodiment of FIG. 2.

However, unlike this latter, in the embodiment of FIG. 3, the receivingsurface of the acquisition means 27 (for example a sensor of C-MOS typewith “rolling shutter” operation) comprises receiving surface portions271 that can be selectively activated to receive the light beam 2.

The receiving surface portions 271 can be selectively activated (bysending suitable control signals) by the control unit 120 through amobile electronic windowing process of the pixels present in thereceiving surface of the acquisition means 27.

Each surface portion 271, when selectively activated by the control unit120, defines a first passage section 2310 for the light beam 2. Thispassage section is optically conjugated with the retina and defines acorresponding light acquisition region 231A on the retina 101.

In practice, each surface portion 271, when selectively activated, hasimilar functions to those of the confocal opening 231 of the mobileconfocal diaphragm 23 described in relation to FIG. 2.

Therefore, in the embodiment of FIG. 3, the apparatus 500 does notcomprise the confocal diaphragm 23. Moreover, the scanning means 17 donot perform descanning of the light beam 2 but are simply arranged todirect the light beam 2 along the optical acquisition path 2A.

Advantageously, the control unit 120 selectively activates the varioussurface portions 271 of the receiving surface of the acquisition means27 synchronously with the movement of the scanning means 17.

In the embodiment of FIG. 3 of the apparatus 500, the first shapingmeans 11 of the light beam 1 are identical to the first shaping meansalready described in relation to FIGS. 1, 7, 8 and 9. They comprise aprojection diaphragm 114 or other shaping means adapted to define apassage section 1141 identical to that of the embodiment of FIG. 1described above.

Instead, the second shaping means comprise the active portion 271 of thereceiving surface of the acquisition means 27 that defines the passagesection 2310.

A further embodiment of the apparatus 500 is shown in FIG. 4.

This embodiment has a structure and operation similar, in many aspects,to the embodiment of FIG. 3.

Unlike this latter, in the embodiment of FIG. 4 the light beam 2 comingfrom the retina is descanned by the scanning means 17 and directedtowards the acquisition means 27 that comprise a TDI sensor having atleast a sensitive surface portion 272 formed by pixels arranged in amatrix on a long and narrow rectangular area.

The sensitive surface portion 272 of the TDI sensor (or the wholesensitive surface of this latter) can be activated by sending suitablecontrol signals by the control unit 120 and defines a second passagesection 2310 for the light beam 2.

This passage section is optically conjugated with the retina and definesa corresponding light acquisition region 231A on the retina 101.

In practice, the sensitive surface portion 272 of the TDI sensor (or thewhole sensitive surface of this latter) has similar functions to thoseof the confocal opening 231 of the confocal diaphragm 23 describedabove.

Therefore, in the embodiment of FIG. 4, the apparatus 500 does notcomprise the confocal diaphragm 23.

In the embodiment of FIG. 4 of the apparatus 500, the first shapingmeans 11 of the light beam 1 are identical to the first shaping meansalready described in relation to FIGS. 1, 7, 8 and 9. They comprise aprojection diaphragm 114 or other shaping means adapted to define apassage section 1141 identical to that of the embodiment of FIG. 1described above.

Instead, the second shaping means comprise the sensitive surface portion272 of the TDI sensor (or the whole sensitive surface of this latter)that defines the passage section 2310.

A further embodiment of the apparatus 500 is shown in FIG. 5.

This embodiment has a structure and operation similar, in many aspects,to the embodiment of FIG. 1.

However, unlike this latter, in the embodiment of FIG. 5, the firstscanning means 17 are adapted to perform circular scanning of the lightbeam 1, i.e., move the light beam 1 projected on the surface of theretina 101 about the rotation axis A, according to the circular secondscanning direction S2.

In the embodiment of FIG. 5 of the apparatus 500, the first shapingmeans 11 of the light beam 1 are identical to the first shaping meansalready described in relation to FIGS. 1, 7, 8 and 9. They comprise aprojection diaphragm 114 or other shaping means adapted to define apassage section 1141 identical to that of the embodiment of FIG. 1described above.

The passage section 1141 defines a projection region 1141A having alinear shape with a length Lil measured along a direction radial withrespect to the second scanning direction S2 and a length Wil measuredalong a direction tangential with respect to the second scanningdirection S2 (FIG. 13).

Moreover, the light projection region 1141A preferably has a length Lilmuch longer than its width Wil. For example, the ratio between the sizesWil/Lil can vary from ⅕ to 1/100.

On the retina 101, the light beam 1 illuminates a light projectionregion 1141A that moves along the retina according to the secondscanning direction S2 imposed by the scanning means 17, traveling over afirst retinal area 1141B.

The same scanning means 17 are adapted to descan the light beam 2 comingfrom the retina transforming it into a fixed beam.

Moreover, the light beam 2 passes through the confocal diaphragm 23 andis received by the acquisition means 27.

The confocal diaphragm 23 preferably comprises at least a confocalopening 231 (of elongated shape) that defines a second passage section2310 for the light beam 2 directed towards the acquisition means 27.This passage section is optically conjugated with the retina and definesa corresponding light acquisition region 231A on the retina 101.

The light acquisition region 231A has a linear shape with a length Limmeasured along a direction radial with respect to the second scanningdirection S2 and a width Wim, measured along a direction tangential withrespect to the second scanning direction S2 (FIG. 13).

Further solutions (not illustrated) to perform circular scanning arepossible.

For example, the first scanning means 17 can be produced as a group oftwo separate assemblies that perform synchronous rotation movements, oneof which rotates the light beam 1 while the other rotates the confocaldiaphragm 23.

Besides the solution that uses a confocal diaphragm 23, other solutions,applicable in the case of an apparatus 500 that performs circularscanning, are possible.

According to an example, similar to the one shown in relation to FIG. 3,the acquisition means 27 can comprise a receiving surface having surfaceportions 271 that can be selectively activated to receive the light beam2.

According to a further example, similar to the one shown in relation toFIG. 4, the acquisition means 27 can comprise a TDI sensor having atleast a sensitive surface portion 272. The sensitive surface portion 272or the whole surface of the sensor TDI define the passage section 2310.

Those skilled in the art will understand that further embodiments of theapparatus 500 directly derivable from the embodiments described above,are possible.

For example, it is possible to produce equipment intended for theacquisition of fluorescence images of the retina by suitably combiningthe configurations illustrated in the FIGS. 1 to 9.

Moreover, in an apparatus 500 produced according to one of theembodiments illustrated in FIGS. 1-5, it is possible to use on thelighting path 1A illumination means 12 containing at least a lightsource 126 capable of emitting an excitation light suitable to excitefluorescent substances of the retina, if necessary together with thefilter means 129, while the filter means 28 described above are used onthe imaging path 2A of the same apparatus.

According to the invention, the above described first shaping means 114and second shaping means 23, 271, 272 of the light beams are arranged sothat (FIGS. 11 and 13):

-   -   the light projection region 1141A and the light acquisition        region 231A are at least partially mutually overlapped;    -   the light projection region 1141A has a length Lil shorter than        the length Lim of the light acquisition region 231A.

Preferably, the projection opening 1140 for the light beam 1 and theconfocal opening 231 (FIG. 1, 2, 5) or 271 (FIG. 3) or 272 (FIG. 4) forthe light beam 2, respectively produced by the first and second shapingmeans described above, are advantageously shaped to define respectivepassage sections 1141, 2310 for the light beams 1, 2 having thefollowing characteristics:

-   -   the passage sections 1141, 2310 have an elongated shape (for        example rectangular or with variable width) and extend along a        corresponding main longitudinal axis;    -   the positions of the passage sections 1141 and 2310, together        with the lenses of the optical lighting path 1A and the lenses        of the optical acquisition path 2A are arranged so that the        conjugates on the retina of the passage sections 1141 and 2310,        i.e., the light projection region 1141A and the light        acquisition region 231A, are oriented in directions parallel to        each other.

In FIG. 11, for an apparatus 500 having scanning means 17 arranged toperform a linear scan of the light beam 1, the light projection region1141A and the light acquisition region 231A, viewed according to a planeparallel to the first scanning direction S1 (practically, as defined onthe retina) are shown separately (references (A)-(B)) and overlapped(reference (C)).

It can be noted how, at the surface of the retina, the light projectionregion 1141A, illuminated by the light beam 1, has a length Lil shorterthan the length Lim of the light acquisition region 231A, from which thelight beam 2 comes at least partially.

Due to the action of the scanning means 17, the light projection region1141A and the light acquisition region 231A move synchronously along theretina, constantly remaining overlapped.

During the synchronous movement of the light projection region 1141A andof the light acquisition region 231A along the retina, the lightprojection region 1141A travels over a first retinal area 1141B (FIG.11-(A)) while the light acquisition region 231A travels over a secondretinal area 231B (FIG. 11-(B)).

As can be seen from FIG. 11-(C), the second retinal area 231B is largerwith respect to the first retinal area 1141B and differs from thislatter by one or more third retinal areas 231D.

Having a longer length Lim and partially overlapping the lightprojection region 1141A, the light acquisition region 231A comprises oneor more non-overlapping portions 231C. These non-overlapping portions,during the synchronous movement of the light projection region 1141A andof the light acquisition region 231A along the retina, travel over thethird retinal areas 231D.

Advantageously, when the light projection region 1141A and the lightacquisition region 231A are centred with respect to each other, thethird retinal areas 231C extend beyond the ends of the projection region1141A.

In the example shown in FIG. 11, the light projection region 1141A andthe light acquisition region 231A have lengths Lil, Lim shorter than thediameter of the available optical field 19A (i.e., of the maximumretinal section that can be observed). This latter is defined by thelenses of the apparatus 500, in particular by the eyepiece 19.

In this case, both retinal areas 1141B, 231B travelled by the lightprojection region 1141A and by the light acquisition region 231A can beobserved by the acquisition means 27.

This solution, although allowing correct acquisition of the images ofthe retina, does not allow the available optical field to be fullyexploited.

In the example shown in FIG. 12, the light projection region 1141A andthe light acquisition region 231A have lengths Lil, Lim respectivelyshorter and longer than the diameter DO of the available optical field19A (FIG. 12-(A)-(B).

In this case, the retinal area 231B travelled by the light acquisitionregion 231A cannot be observed completely by the acquisition means 27but is limited by the (curved) edges of the available optical field 19A(FIG. 12-(C)).

Nonetheless, this solution allows correct acquisition of the images ofthe retina and, simultaneously, allows the available optical field to beexploited to a greater extent.

In FIG. 13, for an apparatus 500 having scanning means 17 arranged toperform a circular scan of the light beam 1, the light projection region1141A and the light acquisition region 231A are shown separately(references (A)-(B)) and overlapped (reference (C)).

The light projection region 1141 and the light acquisition region 231Aare viewed along the rotation axis A of the scanning means 17(practically, as defined on the retina).

It can be noted how at the surface of the retina the light projectionregion 1141A, illuminated by the light beam 1, has a length Lil shorterthan the length Lim of the light acquisition region 231A, from which thelight beam 2 comes at least partially.

Due to the action of the scanning means 17, the light projection region1141A and the light acquisition region 231A perform a rotationalmovement about the axis A, synchronously (with the movement of the firstlight beam 1 imposed by the scanning means 17) remaining constantlyoverlapped.

During the rotational movement of the light projection region 1141A andof the light acquisition region 231A about the axis A, the lightprojection region 1141A travels over a first retinal area 1141B (FIG.13-(A)) while the light acquisition region 231A travels over a secondretinal area 231B (FIG. 13-(B)).

As can be observed from the figure (FIG. 13-(C)), the second retinalarea 231B is larger with respect to the first retinal area 1141B anddiffers from this latter by one or more third retinal areas 231D.

Having a longer length Lim and being partially superimposed on the lightprojection region 1141A, the light acquisition region 231A comprises oneor more non-overlapping portions 231C. These non-overlapping portions,during the synchronous rotation movement of the light projection region1141A and of the light acquisition region 231A along the retina, travelover the third retinal areas 231D.

Advantageously, when the light projection region 1141A and the lightacquisition region 231A are centred with respect to each other, thethird retinal areas 231D form an annulus centred in the rotation axis A.

With reference to FIG. 14, this shows an image I (of reflected orfluorescence light) of the retina acquired by the acquisition means 27when the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A, from which the light beam 2 comes (at least partially).

FIGS. 14(A) and 14(B) show examples of images I in an apparatus 500having scanning means 17 arranged to perform a linear scan of the lightbeam 1 (FIGS. 1-4 and 11-12).

The image I comprises a first light zone SI corresponding to the firstilluminated retinal area 1141B, travelled by the light projection region1141A during the synchronous linear movement of the light projectionregion 1141A and of the light acquisition region 231A along the retina.

FIG. 14(C) shows an image I acquired in an apparatus 500 having scanningmeans 17 arranged to perform a circular scan of the light beam 1 (FIGS.5 and 13).

Also in this case, the image I comprises a first light zone SIcorresponding to the first illuminated retinal area 1141B, travelled bythe light projection region 1141A during the synchronous circularmovement of the light projection region 1141A and of the lightacquisition region 231A about the axis A.

In both cases, the image I comprises one or more second light zones SL,corresponding to the third retinal areas 231C travelled by thenon-overlapping portions 231C between the light acquisition region 231Aand the light projection region 1141A during their synchronous movementon the retina (linear or circular).

The examples of FIGS. 14(A) and 14(B) are particular cases in whichthere are several light zones SL. These cases correspond to an apparatus500 having scanning means 17 arranged to perform a linear scan of thefirst light beam 1 and for which the light acquisition region 231A andthe light projection region 1141A of the retina are centred with eachother. As can be seen, the image I comprises at the centre the firstlight zone SI and, at the edges of this latter, the second light zonesSL.

The example of FIG. 14(C) represents a particular case of an apparatus500 having scanning means 17 arranged to perform a circular scan of thefirst light beam 1 and for which the light acquisition region 231A andthe light projection region 1141A of the retina are both centred withthe axis A. As can be observed, the image I comprises at the centre thefirst light zone SI, in the shape of a disc and, around this, a secondlight zone SL, in the shape of an annulus.

As illustrated above, the first light zone SI represents, in practice,the image on the surface of the acquisition means of the retinal areailluminated by the light beam 1 during the scanning movement of thislatter on the surface of the retina. Consequently, light coming from theretina and parasitic light, mixed together, can simultaneously reach thezone SI.

The zones SL represent retinal areas that are not illuminated by thelight beam 1. Consequently, parasitic light can substantially reach thezones SL.

In use of the apparatus 500 for the acquisition of images obtained withlight reflected by the retina (for example colour images of the retina),this parasitic light is formed of light scattered or reflected fromzones of the eye or of the apparatus 500 that are not conjugated withthe retina 101, in particular, as known, from the crystalline lens ofthe eye 103, especially if affected by cataract.

Part of this parasitic light enters the acquisition path 2A and iscaptured by the acquisition means 27 as a distribution of light thatoverlaps the retinal image.

If coming from zones of the eye or of the apparatus very close to the“scanning pivot” of the light beam 1 (which is normally close to thepupil and to its optical conjugates), this parasitic light determines asubstantially homogeneous distribution of light that overlaps theretinal image.

If coming from zones of the eye or of the apparatus farther from the“scanning pivot” of the light beam 1, the aforesaid parasitic lightdetermines an uneven distribution of light that overlaps the retinalimage.

In any case, in a retinal image, the presence of this parasitic lightoverlapping the retinal image determines a reduction of the contrast ofthis latter (“blurring effects”).

The parasitic light generated through scattering within the crystallinelens overlaps the retinal image more or less homogeneously given that itcomes from a zone of the optical path close to the scanning pivot.

FIG. 16-(A) shows the effect of scattering of the light within thecrystalline lens in the case of acquisition of a retinal image obtainedwith light reflected by the retina.

The light 1 i, scattered in the passage zone 1031 of the beam 1 in thecrystalline lens 103, bounces inside the crystalline lens making itbright.

Part of this parasitic light 1 i scattered within the crystalline lensenters the acquisition path 2A, passes through the confocal opening 231and is more or less homogeneously distributed on both the zones 1141Band 231D of the retina, therefore overlapping the image I of the retinaacquired, in particular at the zones SI and SL of this latter.

In fact, this parasitic light is added to the light coming from thezones 1141B and 231D of the retina and is therefore present in the zonesSI and SL of the image I.

The more or less homogeneous distribution on the zones SI and SL of theimage I of the scattered light within the crystalline lens is justifiedby the fact that the crystalline lens zone that scatters this parasiticlight is very close to the small and almost fixed zone (scanning pivot)through which all the rays that form the light beam 2 that creates thewhole image I pass.

Therefore, the brightness contribution provided by the parasitic lightscattered within the crystalline lens on the zones SI and SL is more orless the same and is measurable at the second light zones SL of theimage I taken by the acquisition means 27.

This information can be used to subtract the contribution of theparasitic light from the zone SI of the retinal image and obtain aretinal image less disturbed by parasitic light.

In use of the apparatus 500 for the acquisition of fluorescence imagesof the retina, this parasitic light is formed by fluorescence lightemitted from zones of the eye that are not conjugated with the retina101, in particular, as known, from the crystalline lens of the eye 103,especially if affected by cataract.

In fact, in the case of capturing a fluorescence retinal image, theparasitic light must have wavelengths corresponding to the bandwidth ofthe filter means 28 to be capable of passing towards the acquisitionmeans 27 and blurring the fluorescence retinal image.

Therefore, in this case, the parasitic light is not produced by ascattering or reflection of the light beam 1 (whose wavelength does notallow passage through the filter means 28), but is produced throughfluorescence, above all within the crystalline lens and in particular ifthis latter is affected by cataract.

As known, the crystalline lens of the eye 103 absorbs blue light andgenerates green fluorescence light. The fluorescence of the crystallinelens is particularly strong in the case of eyes with cataract.

FIG. 16-(B) shows two components of the fluorescence light generated bythe crystalline lens. The component 1Fi of the fluorescence lightgenerated in the passage zone 1031 of the beam 1 through the crystallinelens represents the portion of fluorescence light of the crystallinelens that is scattered within the crystalline lens, making it bright.

Part of the fluorescence light scattered within the crystalline lensmanages to directly enter the acquisition path 2A, passes through thefilter 31 and the confocal opening 231 and overlaps the fluorescenceretinal image acquired.

The fluorescence light 1Fi scattered within the crystalline lens comesfrom a small and almost fixed zone (close to the scanning pivot).Therefore, it causes a more or less homogeneous increase of thefluorescence brightness in the fluorescence retinal image acquired.

Another portion of the fluorescence light generated in the passage zone1031 of the light beam 1 through the crystalline lens is the component1Fr directed towards the retina.

This fluorescence light (green), generated by the crystalline lens,illuminates the retina more or less homogeneously and is subsequentlyreflected by this latter. The part of the light 1Fr reflected by theretina in the overlapped zone between the lighting path and theacquisition path partially enters the acquisition path 2A overlappingthe fluorescence light produced by the retina. The fluorescence light1Fr, reflected by the retina, passes through the filter 31 and theconfocal opening 231 and more or less homogeneously increases thebrightness of the fluorescence retinal image acquired.

The parasitic fluorescence light produced by the components 1Fi and 1Frof the fluorescence light of the crystalline lens causes a decrease inthe contrast of the final fluorescence retinal image.

As illustrated above, part of this parasitic fluorescence light passes(within the crystalline lens) through the acquisition path 2A and iscaptured by the acquisition means 27 as a more or less homogeneousdistribution of fluorescence light that overlaps the retinal image.

In a fluorescence retinal image, the presence of this parasitic lightoverlapping the retinal image determines a reduction of the contrast ofthis image (“blurring effects”).

Given that it comes from a zone of the optical path close to thescanning pivot, the parasitic fluorescence light generated by thefluorescence of the crystalline lens, overlaps on the fluorescenceretinal image more or less homogeneously.

Therefore, the brightness contribution provided by this parasiticfluorescence light generated by the crystalline lens on the zones SI andSL is more or less the same and is measurable at the second light zonesSL of the image acquired.

This information can be used to subtract the contribution of parasiticlight from the zone SI of the fluorescence retinal image and obtain afluorescence retinal image less disturbed by parasitic light.

According to some embodiments of the invention (shown in one of FIGS. 1to 5 together with one of FIG. 8 or 9), the first light beam shapingmeans 11 are adapted to provide also a third passage section 1143 forthe first light beam 1, which is shaped to define a light projectionregion 1143A having a length Lil₂ longer than or equal to the length Limof the light acquisition region 231A (FIG. 15).

In the variant of embodiment of the first shaping means 11 of FIG. 8,the projection opening 1142 of the movable projection diaphragm 114 canadvantageously be shaped to define a third passage section 1143 shapedto define, when coupled with the optical lighting path 1A, with theprojection diaphragm 114 positioned in the second coupling position, alight projection region 1143A having a length Lil₂ longer than or equalto the length Lim of the light acquisition region 231A.

In the variant of embodiment of the first shaping means 11 of FIG. 8,the projection opening 1142 of the projection diaphragm 114 canadvantageously be shaped to define a third passage section 1143 thatdefines, when coupled with the optical lighting path 1A, without beingpartially covered by the mask 118, a light projection region 1143Ahaving a length Lil₂ longer than or equal to the length Lim of the lightacquisition region 231A.

When the first light beam shaping means 114 comprise a third passagesection 1143 of the type illustrated above, the light acquisition region231A travels, along the retina, a second retinal area 231B completelywithin the first illuminated retinal area 1141B, travelled by the lightprojection region 1141A (FIGS. 15-(A) and 15-(B)).

With reference to FIG. 15(C), this shows an image I of the retina (alsocalled “wide field retinal image”) acquired by the acquisition means 27when the light projection region 1141A, illuminated by the light beam 1,has a length longer than or equal to the length Lim of the lightacquisition region 231A, from which the light beam 2 comes at leastpartially.

The image I comprises a single third light zone SLF corresponding to theretinal area 1141B, 231A travelled by the light projection region 1141Aduring the synchronous movement of the light projection region 1141A andof the light acquisition region 231A along the retina.

Due to the first and second light beam shaping means, advantageouslyarranged as illustrated above, the control unit 120 (more in particularthe related data processing means) is capable of executing someprocessing procedures of the images acquired by the acquisition means 27to obtain images with light reflected by the retina (for example colourimages) or improved fluorescence retinal images, in particular withregard to their level of contrast.

In general, to execute these processing procedures, the control unit 120is configured to:

-   -   acquire a retinal image obtained with light reflected by the        retina or a fluorescence retinal image with the first and second        shaping means arranged so that the light projection region        1141A, illuminated by the light beam 1, has a length Lil shorter        than the length Lim of the light acquisition region 231A, from        which the light beam 2 comes. As illustrated above, in this        image, it is possible to observe a first light zone SI and one        or more second light zones SL.    -   acquire detection data indicative of the light level of the        second light zones SL of the retinal image obtained with light        reflected by the retina or fluorescence retinal image;    -   process said retinal image obtained with light reflected by the        retina or fluorescence retinal image based on the aforesaid        detection data to obtain a further retinal image obtained with        light reflected by the retina or a further fluorescence retinal        image improved with respect to the image acquired directly.

For reasons of clarity it is specified that, in general, “retinal imageobtained with light reflected by the retina” means a retinal imageobtained without the filter 31 being in the acquisition path 2A. Thelight reflected by the retina is thus capable of reaching the sensormeans 27 regardless of its wavelength. Examples of images from thiscategory are colour images, infrared images and red-free images.

Some examples of embodiments of the apparatus 500 that illustrate someimage processing procedures executable by the control unit 120 are nowdescribed.

First Image Processing Procedure

In a possible example of embodiment, the control unit 120 is configuredto execute a first image processing procedure with which it is possibleto obtain images obtained with light reflected by the retina improvedwith respect to the images that can be acquired directly by theacquisition means 27.

The aforesaid first processing procedure comprises a step of acquiringan image obtained with light reflected by the retina (for example acolour image).

Advantageously, this retinal image obtained with light reflected by theretina is acquired by the control unit 120 based on the informationprovided by the acquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A, from which the light beam 2 comes at least partially.

Moreover, a light source 121, 123, 124, 126 adapted to provide the typeof light desired is appropriately activated and the filter 31, ifprovided, is decoupled from the optical acquisition path 2A.

As illustrated above, the retinal image obtained with light reflected bythe retina acquired by the control unit 120 has a first light zone SI,having greater brightness, and one or more second light zones SL havingreduced brightness (FIG. 14).

The aforesaid first processing procedure comprises a step of processingthe retinal image obtained with light reflected by the retina, thusacquired, to obtain first detection data indicative of the fluorescencelight level of said second light zones SL.

As illustrated above, the brightness of the second light zones SL is dueto the light scattered or reflected from zones of the eye or of theapparatus 500 that are not conjugated with the retina 101, inparticular, as is known, from the crystalline lens of the eye 103,especially if affected by cataract.

The first detection data thus obtained are therefore indicative of thelight level of the parasitic light present in the retinal image obtainedwith light reflected by the retina, as acquired.

Preferably, the aforesaid first detection data are obtained by measuringin several points the light level at these second zones SL.

The aforesaid first processing procedure comprises a step of processingthe retinal image obtained with light reflected by the retina, asacquired, and the first detection data to obtain a further retinal imageobtained with light reflected by the retina.

In the case in which the retinal image originally acquired has ahomogeneous distribution of parasitic light at the second zones SL(parasitic light source close to the “scanning pivot”), the furtherretinal image obtained with light reflected by the retina can be easilyreconstructed based on the aforesaid first detection data.

In the case in which the retinal image originally acquired has anon-homogeneous distribution of parasitic light (parasitic light sourceat a distance from the “scanning pivot”), at the second zones SL, thefurther retinal image obtained with light reflected by the retina can beobtained by processing the aforesaid detection values based on anappropriate interpolation algorithm, which can be of known type.

Preferably, the processing step executed by the control unit 120 toprovide the further retinal image obtained with light reflected by theretina comprises the construction, based on the aforesaid firstdetection data, of an image indicative of a distribution of parasiticlight in the retinal image originally acquired.

The parasitic light retinal image can have a different extension withrespect to the retinal image obtained with light reflected by the retinaas acquired. For example, it can have an extension corresponding to thefirst light zone SI of the retinal image originally acquired.

Preferably, in this processing step the retinal image originallyacquired is subtracted from the parasitic light retinal image, asconstructed, to obtain a further retinal image obtained with lightreflected by the retina that is less affected by the brightnesscontribution of the unwanted parasitic light.

The further retinal image obtained with light reflected by the retinathus has a reduction of the “blurring” effects caused by the parasiticlight generated in zones of the apparatus 500 or of the eye 100 (inparticular the crystalline lens) that are not conjugated with the retina101.

This further retinal image obtained with light reflected by the retinahas a higher contrast level, facilitating identification of any diseasedretinal zones.

In a variant of embodiment thereof, in which the retina is illuminatedactivating a white light source and a retinal image obtained with lightreflected by the retina (for example a colour image) is acquired, theaforesaid first processing procedure of the images comprises some stepsto improve the tones of colour of the further retinal image obtainedwith light reflected by the retina, processed as illustrated above.

Preferably, the aforesaid first processing procedure of the imagescomprises:

-   -   processing the aforesaid first detection data to obtain first        estimation data indicative of the light absorption by the        crystalline lens of the eye;    -   adjusting one or more colour channels of the further retinal        image obtained with light reflected by the retina based on said        first estimation data.

As is widely known, the passage of light through the crystalline lens ofthe eye is also accompanied by selective absorption phenomena, theextent of which varies with the wavelength of the light that passesthrough the crystalline lens.

More precisely, the amount of light absorbed by the crystalline lensincreases as the wavelength of the light that passes through thecrystalline lens decreases.

Therefore, after having passed through the crystalline lens, the firstlight beam 1, intended to illuminate the retina, will have a spectrumwith a blue component attenuated to a greater extent with respect to thegreen and red components.

For similar reasons, after having passed through the crystalline lens,the second light beam 2, coming from the retina, will have a spectrumwith a blue component further attenuated with respect to the green andred components.

As is known, the amount of light absorbed by the crystalline lensincreases with the opacity of this latter.

Consequently, the colour of a retinal image of an eye with crystallinelens affected by cataract will have a more orange colour tone (as aresult of greater attenuation of the blue component) with respect to thecolour retinal image of a healthy eye (which will have a pinker colourtone).

By appropriately processing (with algorithms that can be of known type)the first detection data indicative of the fluorescence light level ofsaid second light zones SL of the retinal image obtained with lightreflected by the retina, as acquired, it is possible to estimate thelevel of opacity of the crystalline lens and, consequently, obtain firstestimation data indicative of its capacity of differentiated lightabsorption on the wavelength.

Based on the second estimation data indicative of the light absorptionby the crystalline lens of the eye, it is possible to amplify the blue,green and red channels of the further retinal image processed withdifferentiated coefficients of amplification, calculated as a functionof the aforesaid first estimation data.

In this way it is possible to at least partially offset thedifferentiated attenuation as a function of the wavelength of the lightbeams 1, 2 that pass through the crystalline lens.

The further retinal image, thus re-processed, has colours that betterreflect the natural colours of the retina.

Second Image Processing Procedure

In a further example of embodiment, the control unit 120 is configuredto execute a second image processing procedure that makes it possible toobtain improved fluorescence retinal images with respect to thefluorescence images acquired directly by the control unit 120.

The aforesaid second processing procedure comprises a step of acquiringa fluorescence retinal image.

Advantageously, this fluorescence retinal image is acquired by thecontrol unit 120 based on the information provided by the acquisitionmeans 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A from which the light beam 2 comes at least partially.

Moreover, a light source 126 capable of providing an appropriateexcitation light capable of exciting the fluorescent substances presenton the retina is appropriately activated and the filter 31 isadvantageously coupled to the optical acquisition path 2A.

The fluorescence retinal image, thus acquired, has a first light zoneSI, having greater brightness, and one or more second light zones SLhaving reduced brightness (FIG. 14).

The aforesaid second processing procedure comprises a step of processingthe fluorescence retinal image, thus acquired, to obtain seconddetection data indicative of the fluorescence light level at theaforesaid second light zones SL.

As illustrated above, the fluorescence brightness of the second lightzones SL is due to the fluorescence light emitted from zones of the eyethat are not conjugated with the retina 101, in particular, as is known,from the crystalline lens of the eye 103, especially if affected bycataract.

The second detection data thus obtained are therefore indicative of thelight level of the parasitic fluorescence light present in thefluorescence image, as acquired by the control unit 120.

Preferably, the aforesaid second detection data are obtained bymeasuring in several points the fluorescence light level at these secondzones SL.

The aforesaid second processing procedure comprises a step of processingthe fluorescence retinal image, as acquired, and the aforesaid seconddetection data to obtain a further fluorescence retinal image.

Preferably, this processing step comprises the construction, based onthe aforesaid second detection data, of a fluorescence image indicativeof a distribution of the parasitic fluorescence light in thefluorescence retinal image originally acquired.

This parasitic fluorescence light image can have a different extensionwith respect to the fluorescence image originally acquired by thecontrol unit 120. For example, it can have an extension corresponding tothe first light zone SI of the fluorescence retinal image originallyacquired.

Preferably, in this processing step, the parasitic fluorescence lightimage, as constructed, is subtracted from the fluorescence retinalimage, as acquired, to obtain a further fluorescence retinal image thatis less disturbed by the brightness contribution of the parasiticfluorescence light.

The further fluorescence retinal image thus has a reduction of the“blurring” effects caused by the parasitic fluorescence light generatedin zones of the eye 100 (in particular the crystalline lens) that arenot conjugated with the retina 101.

This further fluorescence retinal image has greater contrast,facilitating identification of any diseased retinal zones.

In a variant of embodiment thereof, the second image processingprocedure allows fluorescence images particularly useful to performquantitative measurements of the fluorescence light emitted from theretina to be obtained.

Normally, these quantitative measurements of the fluorescence light arehighly disturbed by the presence of the crystalline lens that:

-   -   absorbs an unknown quantity of excitation light 1 before this        reaches the retina;    -   absorbs an unknown quantity of fluorescence light 2 during its        passage through the crystalline lens;    -   adds to the fluorescence retinal image an unknown quantity of        parasitic light substantially generated through the fluorescence        of the crystalline lens.

According to this variant of embodiment, the aforesaid second processingprocedure comprises a step of receiving a retinal image obtained withlight reflected by the retina.

Advantageously, this retinal image obtained with light reflected by theretina is acquired by the control unit 120 based on the informationprovided by the acquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A from which the light beam 2 comes.

A first preferred solution for acquiring the retinal image obtained withlight reflected by the retina is to activate the excitation source 126and acquire the retinal image, with the filter 31 decoupled from theacquisition path 2A.

A second preferred solution is to acquire a retinal image, activating asource (121, 123, 124) capable of projecting white light, with thefilter 31 decoupled from the acquisition path 2A.

The aforesaid retinal image obtained with light reflected by the retinahas a first light zone SI, having greater luminosity, and one or moresecond light zones SL, having reduced luminosity (FIG. 14).

The aforesaid second processing procedure comprises a step of processingsaid retinal image obtained with light reflected by the retina to obtainfirst detection data indicative of the fluorescence light level of saidsecond light zones SL.

The first detection data, thus obtained, are indicative of the lightlevel of the parasitic light present in the aforesaid retinal imageobtained with light reflected by the retina, as acquired by the controlunit 120.

Therefore, the aforesaid second processing procedure comprises thefollowing steps:

-   -   processing said first detection data to obtain second estimation        data indicative of the level of opacity of the crystalline lens        of the eye to excitation light;    -   processing said second estimation data to obtain third        estimation data indicative of a level of absorption of        fluorescence light by the crystalline lens of the eye;    -   adjusting the brightness of said further fluorescence retinal        image based on said second estimation data and third estimation        data.

By appropriately processing the first detection data indicative of thefluorescence light level of said second light zones SL of the aforesaidfirst retinal image obtained with light reflected by the retina, it ispossible to estimate the level of opacity of the crystalline lens and,consequently, obtain second estimation data regarding the capacity ofexcitation light absorption (light beam 1) by the crystalline lens.

Based on the aforesaid second estimation data, indicative of thecapacity of excitation light absorption by the crystalline lens, it ispossible to adjust the brightness of the further fluorescence retinalimage, as processed, to offset attenuation of the excitation lightcaused by the crystalline lens.

Instead, by appropriately processing the first detection data indicativeof the fluorescence light level of said second light zones SL of theaforesaid first retinal image obtained with light reflected by theretina, it is possible to estimate the level of opacity of thecrystalline lens and, consequently, obtain third estimation dataregarding the capacity of fluorescence retinal light absorption (lightbeam 2) by the crystalline lens.

Based on the aforesaid third estimation data indicative of the capacityof fluorescence light absorption by the crystalline lens, it is possibleto adjust the brightness of the further fluorescence retinal image, asprocessed, to offset the attenuation of fluorescence light 2 caused bythe crystalline lens.

The further fluorescence retinal image thus re-processed can be used toperform quantitative measurements of the fluorescence light, with a highlevel of accuracy.

Third Image Processing Procedure

In a further example of embodiment, the control unit 120 is configuredto execute a third image processing procedure that makes it possible toobtain wide field retinal images obtained with light reflected by theretina improved with respect to the wide field images that can beacquired directly by the control unit 120.

The aforesaid third processing procedure comprises a step of acquiring aretinal image obtained with light reflected by the retina.

Advantageously, this retinal image obtained with light reflected by theretina is acquired by the control unit 120 based on the informationprovided by the acquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A, from which the light beam 2 comes at least partially.

Moreover, a light source 121, 123, 124, 126 adapted to provide the typeof light desired is appropriately activated and the filter means 28, ifprovided, are decoupled from the optical acquisition path 2A.

As illustrated above, the retinal image obtained with light reflected bythe retina, as acquired, has a first light zone SI, having greaterluminosity, and one or more second light zones SL having reducedluminosity (FIG. 14).

The aforesaid first processing procedure comprises a step of processingthe retinal image obtained with light reflected by the retina, asacquired, to obtain first detection data indicative of the fluorescencelight level of said second light zones SL.

The first detection data thus obtained are therefore indicative of thelight level of the parasitic light present in the aforesaid retinalimage obtained with light reflected by the retina, as acquired by thecontrol unit 120.

Preferably, the aforesaid first detection data are obtained by measuringin several points the light level at these second zones SL.

The aforesaid third processing procedure comprises a step of receiving awide field retinal image obtained with light reflected by the retina.

Advantageously, this wide field retinal image obtained with lightreflected by the retina is acquired by the control unit 120 based on theinformation provided by the acquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil longer than or equal to the length Lim of the lightacquisition region 231A from which the light beam 2 comes at leastpartially (FIG. 15).

Moreover, a light source 121, 123, 124, 126 adapted to provide the typeof light desired is appropriately activated and any filter means 28 aredecoupled from the optical acquisition path 2A.

As illustrated above, the wide field retinal image obtained with lightreflected by the retina, as acquired, has a third light zone SFL (FIG.15).

The aforesaid third processing procedure comprises a step of processingthe aforesaid first wide field retinal image obtained with lightreflected by the retina, as acquired, and the aforesaid first detectiondata to obtain a further wide field retinal image obtained with lightreflected by the retina.

Preferably, in this processing step:

-   -   the first detection data are processed to obtain a parasitic        light image indicative of the light level of the parasitic light        present in the retinal image obtained with light reflected by        the retina, originally acquired;    -   the parasitic light image is processed to obtain a wide field        parasitic light image indicative of the light level of the        parasitic light present in the wide field retinal image obtained        with light reflected by the retina, as acquired;    -   the wide field parasitic light image, as constructed, is        subtracted from the wide field retinal image obtained with light        reflected by the retina, as acquired, to obtain a further wide        field retinal image obtained with light reflected by the retina        less disturbed by the brightness contribution of the unwanted        parasitic light.

The further wide field retinal image, thus processed, has a reduction ofthe “blurring” effects caused by the parasitic light generated in zonesof the apparatus 500 or of the eye 100 (in particular of the crystallinelens 103) that are not conjugated with the retina 101.

This further wide field retinal image obtained with light reflected bythe retina has a higher contrast level, facilitating identification ofany diseased retinal zones.

In a variant of embodiment thereof, in which the retina is illuminatedactivating a white light source and acquiring a wide field retinal imageobtained with light reflected by the retina, analogously to what wasillustrated for the first processing procedure described above, theaforesaid third image processing procedure comprises some steps toimprove the colour tone of the further wide field retinal image obtainedwith light reflected by the retina.

Preferably, the third processing procedure comprises:

-   -   processing the aforesaid first detection data to obtain first        estimation data indicative of the light absorption by the        crystalline lens of the eye;    -   adjusting one or more colour channels of said further wide field        retinal image obtained with light reflected by the retina based        on said first estimation data.

The further wide field retinal image obtained with light reflected bythe retina thus re-processed has colours that better reflect the naturalcolours of the retina.

Fourth Image Processing Procedure

In a further example of embodiment, the control unit 120 is configuredto execute a fourth image processing procedure that that makes itpossible to obtain improved wide field fluorescence retinal images withrespect to the wide field fluorescence images that can be acquireddirectly by the control unit 120.

The aforesaid fourth processing procedure comprises a step of acquiringa fluorescence retinal image.

Advantageously, this fluorescence retinal image is acquired by thecontrol unit 120 based on the information provided by the acquisitionmeans 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A, from which the light beam 2 comes.

Moreover, a light source 126 capable of providing a suitable excitationlight capable of exciting the fluorescent substances present on theretina is activated and the filter 31 is advantageously coupled to theoptical acquisition path 2A.

The fluorescence retinal image, as acquired, has a first light zone SI,having greater luminosity, and one or more second light zones SL havingreduced luminosity (FIG. 14).

The aforesaid fourth processing procedure comprises a step of processingthe fluorescence retinal image, as acquired, to obtain second detectiondata indicative of the fluorescence light level at the aforesaid secondlight zones SL.

The second detection data thus obtained are indicative of the lightlevel of the fluorescence parasitic light present in the aforesaidfluorescence retinal image, as acquired by the control unit 120.

Preferably, the aforesaid first detection data are obtained by measuringin several points the fluorescence light level at these second zones SL.

The aforesaid fourth processing procedure comprises a step of receivinga wide field fluorescence retinal image.

Advantageously, this wide field fluorescence retinal image is acquiredby the control unit 120 based on the information provided by theacquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil longer than or equal to the length Lim of the lightacquisition region 231A, from which the light beam 2 comes.

As illustrated above, the wide field fluorescence retinal image has athird light zone SFL (FIG. 15).

The aforesaid fourth processing procedure comprises a step of processingthe wide field fluorescence retinal image and the aforesaid firstdetection data to obtain a further wide field fluorescence retinalimage.

Preferably, in this processing step:

-   -   the first detection data are processed to obtain a parasitic        light image indicative of the light level of the parasitic light        present in the fluorescence retinal image, as acquired;    -   the parasitic light image is processed to obtain a wide field        parasitic light image indicative of the light level of the        fluorescence parasitic light present in the wide field        fluorescence retinal image;    -   the wide field parasitic light image, as constructed, is        subtracted from the wide field fluorescence retinal image, as        acquired, to obtain a further wide field fluorescence retinal        image that is less disturbed by the brightness contribution of        the unwanted fluorescence parasitic light.

The further wide field fluorescence retinal image, thus processed, has areduction of the “blurring” effects caused by the fluorescence parasiticlight generated in zones of the apparatus 500 or of the eye 100 (inparticular of the crystalline lens 103) that are not conjugated with theretina 101.

This further wide field fluorescence retinal image has greater contrast,facilitating identification of any diseased retinal zones.

In a variant of embodiment thereof, the fourth image processingprocedure makes it possible to obtain wide field fluorescence imagesparticularly useful for performing quantitative measurements of thefluorescence light emitted by the retina.

According to this variant of embodiment, the aforesaid second processingprocedure comprises a step of acquiring a retinal image obtained withlight reflected by the retina.

Advantageously, this retinal image obtained with light reflected by theretina is acquired by the control unit 120 based on the informationprovided by the acquisition means 27.

For this acquisition, the first and second shaping means are arranged sothat the light projection region 1141A, illuminated by the light beam 1,has a length Lil shorter than the length Lim of the light acquisitionregion 231A, from which the light beam 2 comes.

A first preferred solution to obtain the retinal image obtained withlight reflected by the retina is to activate the excitation source 126and acquire the retinal image with the filter means 28 decoupled fromthe acquisition path 2A.

A second preferred solution is to acquire a retinal image obtained withlight reflected by the retina activating a source 121, 123, 124 capableof projecting white light with the filter means 28 decoupled from theacquisition path 2A.

The aforesaid retinal image obtained with light reflected by the retinahas a first light zone SI, having greater luminosity, and one or moresecond light zones SL having reduced luminosity (FIG. 14).

The aforesaid fourth processing procedure comprises a step of processingthe retinal image obtained with light reflected by the retina, asacquired; to obtain first detection data indicative of the fluorescencelight level of said second light zones SL.

The first detection data thus obtained are indicative of the light levelof the parasitic light present in the aforesaid retinal image obtainedwith light reflected by the retina, as acquired by the control unit 120.

Therefore, the aforesaid fourth processing procedure comprises thefollowing steps:

-   -   processing the first detection data to obtain second estimation        data indicative of the level of opacity of the crystalline lens        of the eye to excitation light;    -   processing said second estimation data to obtain third        estimation data indicative of a level of fluorescence light        absorption by the crystalline lens of the eye;    -   adjusting the brightness of said further wide field fluorescence        retinal image based on said second and third estimation data.

By appropriately processing the first detection data indicative of thefluorescence light level of said second light zones SL of the retinalimage obtained with light reflected by the retina, as acquired, it ispossible to estimate the level of opacity of the crystalline lens and,consequently, obtain second estimation data indicative of the capacityof excitation light absorption (light beam 1) by the crystalline lens.

Based on the aforesaid second estimation data, indicative of thecapacity of excitation light absorption by the crystalline lens, it ispossible to adjust the brightness of the further wide field fluorescenceretinal image processed, to offset attenuation of the excitation lightcaused by the crystalline lens.

By appropriately processing the first detection data indicative of thefluorescence light level of said second light zones SL of the aforesaidfirst retinal image obtained with light reflected by the retina, it ispossible to estimate the level of opacity of the crystalline lens and,consequently, obtain third estimation data regarding the capacity offluorescence retinal light absorption (light beam 2) by the crystallinelens.

Based on the aforesaid third estimation data indicative of the capacityof fluorescence light absorption by the crystalline lens, it is possibleto adjust the brightness of the further wide field fluorescence retinalimage to offset attenuation of the fluorescence light caused by thecrystalline lens.

The further wide field fluorescence retinal image thus re-processed canbe used to perform quantitative measurements of the fluorescence lightwith a high level of accuracy.

The apparatus 500 according to the invention has considerable advantageswith respect to prior art.

The production of the first and second light beam shaping means arrangedto obtain a light projection region 1141A with length shorter than thelight acquisition region 231A makes it possible to obtain improvedretinal images (obtained with light reflected by the retina orfluorescence light—if necessary also wide field) with a high level ofcontrast, more natural colour tones, brightness influenced to a lesserextent by parasitic light generated or scattered by the crystalline lensand by light absorption by the crystalline lens and a lower probabilityof artifacts.

The apparatus 500 has a very compact structure and is easy to produce onan industrial scale, with considerable advantages in terms of limitingproduction costs.

The invention claimed is:
 1. An eye fundus inspection apparatus,comprising: illumination means comprising at least a light source andadapted to project a first light beam towards a retina of an eye via anoptical lighting path; acquisition means adapted to receive a secondlight beam coming from the retina via an optical acquisition path;scanning means adapted to scan said first light beam on the retina witha linear movement according to a rectilinear first scanning direction,or with a circular movement about a rotation axis according to acircular second scanning direction; light beam separating means adaptedto define separated passage zones for said first and second light beamsat a pupil of the eye; first light beam shaping means adapted to providea first passage section for said first light beam along said opticallighting path, said first passage section being arranged in a positionoptically conjugated with the retina and defining, on the retina, alight projection region at which said first light beam is projected onthe retina, said light projection region having a linear shape with alength measured along a direction perpendicular to said first scanningdirection or along a direction radial to said second scanning directionand a width measured along a direction parallel to said first scanningdirection or along a direction tangential to said second scanningdirection; second light beam shaping means adapted to provide a secondpassage section for said second light beam along said opticalacquisition path, said second passage section being arranged in aposition optically conjugated with the retina and defining, on theretina, a light acquisition region from which said second light beamcomes at least partially, said light acquisition region having a linearshape with a length measured along a direction perpendicular to saidfirst scanning direction or along a direction radial to said secondscanning direction and a width measured along a direction parallel tosaid first scanning direction or along a direction tangential to saidsecond scanning direction; said light projection region and said lightacquisition region at least partially overlapping one another and movingsynchronously with respect to the retina according to said firstscanning direction or said second scanning direction, said lightprojection region having a length shorter than the length of said lightacquisition region.
 2. The eye fundus inspection apparatus of claim 1,wherein: said first light beam shaping means are also adapted to providea third passage section for said first light beam along said opticallighting path, said third passage section being arranged in a positionoptically conjugated with the retina and defining, on the retina, afurther light projection region at which said first light beam isprojected on the retina, said further light projection region having alinear shape with a length measured along a direction perpendicular tosaid first scanning direction or along a direction radial to said secondscanning direction and a width measured along a direction parallel tosaid first scanning direction or along a direction tangential to saidsecond scanning direction, said further light projection region having alength larger than or equal to the length of said light acquisitionregion.
 3. The eye fundus inspection apparatus of claim 2, wherein: saidfirst light beam shaping means comprise a projection diaphragm, saidprojection diaphragm comprising a first projection opening adapted todefine said first passage section for said first light beam and a secondprojection opening adapted to define said third passage section for saidfirst light beam, said projection diaphragm being movable between atleast a first coupling position with said optical lighting path, atwhich said first projection opening is optically coupled with saidoptical lighting path, and a second coupling position with said opticallighting path, at which said second projection opening is coupled withsaid optical lighting path.
 4. The eye fundus inspection apparatus ofclaim 2, wherein: said first light beam shaping means comprise aprojection diaphragm, said projection diaphragm comprising a secondprojection opening adapted to define said third passage section for saidfirst light beam, said projection diaphragm being operatively coupledwith a mask movable in a first masking position, at which said mask doesnot cover said second projection opening, and in a second maskingposition, at which said mask partially covers said second projectionopening to obtain a first projection opening adapted to define saidfirst passage section for said first light beam.
 5. The eye fundusinspection apparatus of claim 1, wherein: said second light beam shapingmeans comprise a confocal diaphragm comprising a confocal openingadapted to define said second passage section for said second lightbeam.
 6. The eye fundus inspection apparatus of claim 1, furthercomprising a control unit adapted to control operation of saidinspection apparatus, and wherein: said second light beam shaping meanscomprise a light receiving surface of said acquisition means; said lightreceiving surface comprises one or more surface portions that can beselectively activated by said control unit; and each surface portion,when activated by said control unit, is adapted to define said secondpassage section for said second light beam.
 7. The eye fundus inspectionapparatus of claim 1, wherein: said second light beam shaping meanscomprise at least a light receiving surface portion of a TDI sensor ofsaid acquisition means, said at least a light receiving surface portionbeing adapted to define said second passage section for said secondlight beam.
 8. The eye fundus inspection apparatus of claim 1, wherein:said illumination means comprise an excitation light source capable ofexciting fluorescent substances on the retina and optically coupled withsaid optical lighting path, said inspection apparatus comprising firstfiltering means of said second light beam arranged along said opticalacquisition path.
 9. The eye fundus inspection apparatus of claim 8,wherein: said first filtering means comprise a filter movable between acoupling position and a decoupling position with said opticalacquisition path.
 10. The eye fundus inspection apparatus of claim 1,further comprising a control unit adapted to acquire at least a retinalimage having a first light zone corresponding to a first retinal areatravelled by said light projection region during a synchronous movementof said light projection region and said light acquisition region withrespect to the retina and one or more second light zones correspondingto one or more third retinal areas travelled by one or morenon-overlapping portions between said light projection region and saidlight acquisition region during the synchronous movement of said lightprojection region and said light acquisition region with respect to theretina.
 11. The eye fundus inspection apparatus of claim 10, whereinsaid control unit is further configured to: acquire a fluorescenceretinal image, said fluorescence retinal image having said first lightzone and said second light zones; process said fluorescence retinalimage to obtain second detection data indicative of the fluorescencelight level of said second light zones; and process said fluorescenceretinal image and said second detection data to obtain a furtherfluorescence retinal image.
 12. The eye fundus inspection apparatus ofclaim 11, wherein said control unit is further configured to: acquire aretinal image obtained with light reflected by the retina, said retinalimage obtained with light reflected by the retina having said firstlight zone and said second light zones; process said retinal imageobtained with light reflected by the retina to obtain first detectiondata indicative of the light level of said second light zones; processsaid first detection data to obtain second estimation data indicative ofa level of opacity of the crystalline lens of the eye to an excitationlight projected on the retina; process said second estimation data toobtain third estimation data indicative of a level of fluorescence lightabsorption by the crystalline lens of the eye; and adjust the brightnessof said further fluorescence retinal image based on said second andthird estimation data.
 13. The eye fundus inspection apparatus of claim1, further comprising a control unit adapted to acquire at least a widefield retinal image having a third light zone corresponding to a thirdretinal area travelled by said light projection region during asynchronous movement of said light projection region and said lightacquisition region with respect to the retina.
 14. The eye fundusinspection apparatus of claim 13, wherein said control unit is furtherconfigured to: acquire a retinal image obtained with light reflected bythe retina, said retinal image obtained with light reflected by theretina having said first light zone and said second light zones; processsaid retinal image obtained with light reflected by the retina to obtainfirst detection data indicative of the light level of said second lightzones; and process said retinal image obtained with light reflected bythe retina and said first detection data to obtain a further retinalimage obtained with light reflected by the retina.
 15. The eye fundusinspection apparatus of claim 14, wherein said control unit is furtherconfigured to: process said first detection data to obtain firstestimation data indicative of light absorption by the crystalline lensof the eye; and adjust one or more colour channels of said furtherretinal image obtained with light reflected by the retina based on saidfirst estimation data.
 16. The eye fundus inspection apparatus of claim13, wherein said control unit is further configured to: acquire aretinal image obtained with light reflected by the retina, said retinalimage obtained with light reflected by the retina having said firstlight zone and said second light zones; process said retinal imageobtained with light reflected by the retina to obtain first detectiondata indicative of the light level of said second light zones; acquire awide field retinal image obtained with light reflected by the retina,said wide field retinal image obtained with light reflected by theretina having said third light zone; and process said wide field retinalimage obtained with light reflected by the retina and said firstdetection data to obtain a further wide field retinal image obtainedwith light reflected by the retina.
 17. The eye fundus inspectionapparatus of claim 16, wherein said control unit is further configuredto: process said first detection data to obtain first estimation dataindicative of the light absorption by the crystalline lens of the eye;and adjust one or more colour channels of said further wide fieldretinal image obtained with light reflected by the retina based on saidfirst estimation data.
 18. The eye fundus inspection apparatus of claim13, wherein said control unit is further configured to: acquire afluorescence retinal image, said fluorescence retinal image having saidfirst light zone and said second light zones; process said fluorescenceretinal image to obtain second detection data indicative of thefluorescence light level of said second light zones; acquire a widefield fluorescence retinal image, said wide field fluorescence retinalimage having said third light zone; and process said wide fieldfluorescence retinal image and said second detection data to obtain afurther wide field fluorescence retinal image.
 19. The eye fundusinspection apparatus of claim 18, wherein said control unit is furtherconfigured to: acquire a retinal image obtained with light reflected bythe retina, said retinal image obtained with light reflected by theretina having said first light zone and said second light zones; processsaid retinal image obtained with light reflected by the retina to obtainfirst detection data indicative of the light level of said second lightzones; process said first detection data to obtain second estimationdata indicative of a level of opacity of the crystalline lens of the eyeto an excitation light used to illuminate the retina; process saidsecond estimation data to obtain third estimation data indicative of alevel of fluorescence light absorption by the crystalline lens of theeye; and adjust the brightness of said further wide field fluorescenceretinal image based on said second and third estimation data.
 20. Amethod comprising: projecting a first light beam from at least a lightsource towards a retina of an eye via an optical lighting path;receiving a second light beam coming from the retina via an opticalacquisition path; scanning said first light beam on the retina with alinear movement according to a rectilinear first scanning direction, orwith a circular movement about a rotation axis according to a circularsecond scanning direction; separating the first light beam from thesecond light beam at a pupil of the eye; providing a first passagesection for said first light beam along said optical lighting path, saidfirst passage section being arranged in a position optically conjugatedwith the retina and defining, on the retina, a light projection regionat which said first light beam is projected on the retina, said lightprojection region having a linear shape with a length measured along adirection perpendicular to said first scanning direction or along adirection radial to said second scanning direction and a width measuredalong a direction parallel to said first scanning direction or along adirection tangential to said second scanning direction; providing asecond passage section for said second light beam along said opticalacquisition path, said second passage section being arranged in aposition optically conjugated with the retina and defining, on theretina, a light acquisition region from which said second light beamcomes at least partially, said light acquisition region having a linearshape with a length measured along a direction perpendicular to saidfirst scanning direction or along a direction radial to said secondscanning direction and a width measured along a direction parallel tosaid first scanning direction or along a direction tangential to saidsecond scanning direction; wherein said light projection region and saidlight acquisition region at least partially overlap one another and movesynchronously with respect to the retina according to said firstscanning direction or said second scanning direction, said lightprojection region having a length shorter than the length of said lightacquisition region.